The ghazal is a poetic form consisting of rhyming couplets and a refrain, with each line sharing the same meter. A ghazal may be understood as a poetic expression of both the pain of loss or separation and the beauty of love in spite of that pain. The form is ancient, originating in Arabic poetry in Arabia long before the birth of Islam. The term Ghazal is of North African and Middle Eastern origin. Its root term in Arabic is " gh-zl " and is derived from the Arabian panegyricqasida. The structural requirements of the ghazal are similar in stringency to those of the Petrarchan sonnet. In style and content it is a genre that has proved capable of an extraordinary variety of expression around its central themes of love and separation. It is one of the principal poetic forms which the Indo-Perso-Arabic civilization offered to the eastern Islamic world.

The ghazal spread into South Asia in the 12th century due to the influence of Sufi mystics and the courts of the new Islamic Sultanate. Although the ghazal is most prominently a form of Dari poetry and Urdu poetry, today it is found in the poetry of many languages of the Indian sub-continent.

The ghazal not only has a specific form, but traditionally deals with just one subject: love, specifically an unconditional and superior love. Ghazals from the Indian sub-continent have an influence of Islamic Mysticism and the subject of love can usually be interpreted for a higher being or for a mortal beloved. The love is always viewed as something that will complete a human being, and if attained will lift him or her into the ranks of the wise, or will bring satisfaction to the soul of the poet. Traditional ghazal love may or may not have an explicit element of sexual desire in it, and the love may be spiritual. The love may be directed to either a man or a woman.[3]

The ghazal is always written from the point of view of the unrequited lover whose beloved is portrayed as unattainable. Most often either the beloved does not return the poet's love or returns it without sincerity, or else the societal circumstances do not allow it. The lover is aware and resigned to this fate but continues loving nonetheless; the lyrical impetus of the poem derives from this tension. Representations of the lover's powerlessness to resist his feelings often include lyrically exaggerated violence. The beloved's power to captivate the speaker may be represented in extended metaphors about the "arrows of his eyes", or by referring to the beloved as an assassin or a killer. Take for example the following couplets from Amir Khusro's Persian ghazal Nami danam chi manzil buud shab:

I wonder what was the place where I was last night,
All around me were half-slaughtered victims of love, tossing about in agony.
There was a nymph-like beloved with cypress-like form and tulip-like face,
Ruthlessly playing havoc with the hearts of the lovers.

It is not possible to gain a full understanding of ghazal poetry without at least being familiar with some concepts of Sufism.[citation needed] Many of the major historical ghazal poets were either avowed Sufis themselves (like Rumi or Hafiz), or were sympathizers with Sufi ideas. Most ghazals can be viewed in a spiritual context, with the Beloved being a metaphor for God, or the poet's spiritual master. It is the intense Divine Love of Sufism that serves as a model for all the forms of love found in ghazal poetry.

Most ghazal scholars today recognize that some ghazal couplets are exclusively about Divine Love (ishq-e-haqiqi), others are about "earthly love" (ishq-e-majazi), but many of them can be interpreted in either context.

Traditionally invoking melancholy, love, longing, and metaphysical questions, ghazals are often sung by Afghan, Pakistani, and Indian musicians. The form has roots in seventh-century Arabia, and gained prominence in the thirteenth- and fourteenth-century thanks to such Persian poets as Rumi and Hafiz and later due to Indian poets such as Mirza Ghalib. In the eighteenth-century, the ghazal was used by poets writing in Urdu. Among these poets, Ghalib is the recognized master.

Enormous collections of ghazal have been created by hundreds of well-known poets over the past thousand years in Persian, Turkish, and Urdu, as well as in the Central Asian Turkic languages. Ghazal poems are performed in Uzbek-Tajik Shashmakom, Turkish Makam, Persian Dastgah and Uyghur Muqam. There are many published translations from Persian and Turkish by Annemarie Schimmel, Arthur John Arberry, and many others.

Ghazal "Gayaki", the art of singing or performing the ghazal in the Indian classical tradition, is very old. Singers like Ustad Barkat Ali and many other singers in the past used to practice it, but due to the lack of historical records, many names are anonymous. It was with Begum Akhtar, and later on Ustad Mehdi Hassan, that classical rendering of ghazals became popular amongst the masses. The categorization of ghazal singing as a form of "light classical" music is a misconception. Classical ghazals are difficult to render because of the varying moods of the "shers" or couplets in the ghazal. Ustad Amanat Ali Khan, Begum Akhtar, Mehdi Hassan, Abida Parveen, Jagjit Singh, Farida Khanum and Ustad Ghulam Ali, Moinuddin Ahamed, are popular classical ghazal singers.

In North India, in addition to Hindustani, ghazals have been very popular in the Gujarati language. For around a century, starting with Balashankar Kantharia, there have been many notable Gujarati ghazal writers like Barkat Virani 'Befaam', Aasim Randeri, Shunya Palanpuri, Amrut 'Ghayal', Khalil Dhantejvi and many more. Some of the notable ghazals of these prominent writers have been sung by Bollywood playback singer Manhar Udhas (the elder brother of noted Ghazal singer Pankaj Udhas).

Renowned ghazal singer, and pioneer of Telugu ghazals, Dr. Ghazal Srinivas popularized the ghazal in Telugu language. Srinivas also introduced ghazal singing in Kannada language, and ghazals in Kannada language were written by Markandapuram Srinivas.

First true-to-form Bangla (Bengali) ghazal are published in "gajaler aayanaay" by Bratish Dashgupta.

The Canadian classical ghazal singer Cassius Khan has the unusual talent of singing in the recitational style whilst accompanying himself on the tabla.

After nearly a century of "false starts" — that is, early experiments by James Clarence Mangan, James Elroy Flecker, Adrienne Rich, Phyllis Webb, etc., many of which did not adhere wholly or in part to the traditional principles of the form, experiments dubbed as "the bastard ghazal"[4] — the ghazal finally began to be recognized as a viable closed form in English-language poetry sometime in the early to mid-1990s. This came about largely as a result of serious, true-to-form examples being published by noted American poets John Hollander, W. S. Merwin and Elise Paschen, as well as by Kashmiri-American poet Agha Shahid Ali, who had been teaching and spreading word of the ghazal at American universities over the previous two decades.

In 1996, Ali compiled and edited the world's first anthology of English-language ghazals, published by Wesleyan University Press in 2000 as Ravishing DisUnities: Real Ghazals in English. (Fewer than one in ten of the ghazals collected in Real Ghazals in English observe the constraints of the form.)

A ghazal is composed of couplets, five or more. The couplets may have nothing to do with one another, except for the formal unity derived from a strict rhyme and rhythm pattern.

A ghazal in English that observes the traditional restrictions of the form:

Where are you now? Who lies beneath your spell tonight?
Whom else from rapture’s road will you expel tonight?